2 files changed, 194 insertions, 0 deletions
diff --git a/core/fxcrt/cfx_blockbuffer.cpp b/core/fxcrt/cfx_blockbuffer.cpp
new file mode 100644
index 0000000000..354f415282
--- /dev/null
+++ b/core/fxcrt/cfx_blockbuffer.cpp
@@ -0,0 +1,140 @@
+// Copyright 2017 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
+
+#include "core/fxcrt/cfx_blockbuffer.h"
+
+#include <algorithm>
+
+#include "third_party/base/stl_util.h"
+
+CFX_BlockBuffer::CFX_BlockBuffer(int32_t iAllocStep)
+    : m_iDataLength(0),
+      m_iBufferSize(0),
+      m_iAllocStep(iAllocStep),
+      m_iStartPosition(0) {}
+
+CFX_BlockBuffer::~CFX_BlockBuffer() {
+  ClearBuffer();
+}
+
+wchar_t* CFX_BlockBuffer::GetAvailableBlock(int32_t& iIndexInBlock) {
+  iIndexInBlock = 0;
+  if (m_BlockArray.empty())
+    return nullptr;
+
+  int32_t iRealIndex = m_iStartPosition + m_iDataLength;
+  if (iRealIndex == m_iBufferSize) {
+    m_BlockArray.emplace_back(FX_Alloc(wchar_t, m_iAllocStep));
+    m_iBufferSize += m_iAllocStep;
+    return m_BlockArray.back().get();
+  }
+  iIndexInBlock = iRealIndex % m_iAllocStep;
+  return m_BlockArray[iRealIndex / m_iAllocStep].get();
+}
+
+bool CFX_BlockBuffer::InitBuffer(int32_t iBufferSize) {
+  ClearBuffer();
+  int32_t iNumOfBlock = (iBufferSize - 1) / m_iAllocStep + 1;
+  for (int32_t i = 0; i < iNumOfBlock; i++)
+    m_BlockArray.emplace_back(FX_Alloc(wchar_t, m_iAllocStep));
+
+  m_iBufferSize = iNumOfBlock * m_iAllocStep;
+  return true;
+}
+
+void CFX_BlockBuffer::SetTextChar(int32_t iIndex, wchar_t ch) {
+  if (iIndex < 0) {
+    return;
+  }
+  int32_t iRealIndex = m_iStartPosition + iIndex;
+  int32_t iBlockIndex = iRealIndex / m_iAllocStep;
+  int32_t iInnerIndex = iRealIndex % m_iAllocStep;
+  int32_t iBlockSize = pdfium::CollectionSize<int32_t>(m_BlockArray);
+  if (iBlockIndex >= iBlockSize) {
+    int32_t iNewBlocks = iBlockIndex - iBlockSize + 1;
+    do {
+      m_BlockArray.emplace_back(FX_Alloc(wchar_t, m_iAllocStep));
+      m_iBufferSize += m_iAllocStep;
+    } while (--iNewBlocks);
+  }
+  wchar_t* pTextData = m_BlockArray[iBlockIndex].get();
+  pTextData[iInnerIndex] = ch;
+  m_iDataLength = std::max(m_iDataLength, iIndex + 1);
+}
+
+int32_t CFX_BlockBuffer::DeleteTextChars(int32_t iCount, bool bDirection) {
+  if (iCount <= 0)
+    return m_iDataLength;
+
+  if (iCount >= m_iDataLength) {
+    Reset(false);
+    return 0;
+  }
+  if (bDirection) {
+    m_iStartPosition += iCount;
+    m_iDataLength -= iCount;
+  } else {
+    m_iDataLength -= iCount;
+  }
+  return m_iDataLength;
+}
+
+void CFX_BlockBuffer::GetTextData(CFX_WideString& wsTextData,
+                                  int32_t iStart,
+                                  int32_t iLength) const {
+  wsTextData.clear();
+  int32_t iMaybeDataLength = m_iBufferSize - 1 - m_iStartPosition;
+  if (iStart < 0 || iStart > iMaybeDataLength) {
+    return;
+  }
+  if (iLength == -1 || iLength > iMaybeDataLength) {
+    iLength = iMaybeDataLength;
+  }
+  if (iLength <= 0) {
+    return;
+  }
+  wchar_t* pBuf = wsTextData.GetBuffer(iLength);
+  if (!pBuf) {
+    return;
+  }
+  int32_t iStartBlockIndex = 0;
+  int32_t iStartInnerIndex = 0;
+  TextDataIndex2BufIndex(iStart, iStartBlockIndex, iStartInnerIndex);
+  int32_t iEndBlockIndex = 0;
+  int32_t iEndInnerIndex = 0;
+  TextDataIndex2BufIndex(iStart + iLength, iEndBlockIndex, iEndInnerIndex);
+  int32_t iPointer = 0;
+  for (int32_t i = iStartBlockIndex; i <= iEndBlockIndex; i++) {
+    int32_t iBufferPointer = 0;
+    int32_t iCopyLength = m_iAllocStep;
+    if (i == iStartBlockIndex) {
+      iCopyLength -= iStartInnerIndex;
+      iBufferPointer = iStartInnerIndex;
+    }
+    if (i == iEndBlockIndex) {
+      iCopyLength -= ((m_iAllocStep - 1) - iEndInnerIndex);
+    }
+    wchar_t* pBlockBuf = m_BlockArray[i].get();
+    memcpy(pBuf + iPointer, pBlockBuf + iBufferPointer,
+           iCopyLength * sizeof(wchar_t));
+    iPointer += iCopyLength;
+  }
+  wsTextData.ReleaseBuffer(iLength);
+}
+
+void CFX_BlockBuffer::TextDataIndex2BufIndex(const int32_t iIndex,
+                                             int32_t& iBlockIndex,
+                                             int32_t& iInnerIndex) const {
+  ASSERT(iIndex >= 0);
+  int32_t iRealIndex = m_iStartPosition + iIndex;
+  iBlockIndex = iRealIndex / m_iAllocStep;
+  iInnerIndex = iRealIndex % m_iAllocStep;
+}
+
+void CFX_BlockBuffer::ClearBuffer() {
+  m_iBufferSize = 0;
+  m_BlockArray.clear();
+}
diff --git a/core/fxcrt/cfx_blockbuffer.h b/core/fxcrt/cfx_blockbuffer.h
new file mode 100644
index 0000000000..dbf01a938a
--- /dev/null
+++ b/core/fxcrt/cfx_blockbuffer.h
@@ -0,0 +1,54 @@
+// Copyright 2017 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
+
+#ifndef CORE_FXCRT_CFX_BLOCKBUFFER_H_
+#define CORE_FXCRT_CFX_BLOCKBUFFER_H_
+
+#include <stdint.h>
+
+#include <memory>
+#include <vector>
+
+#include "core/fxcrt/fx_string.h"
+
+class CFX_BlockBuffer {
+ public:
+  explicit CFX_BlockBuffer(int32_t iAllocStep = 1024 * 1024);
+  ~CFX_BlockBuffer();
+
+  bool InitBuffer(int32_t iBufferSize = 1024 * 1024);
+  bool IsInitialized() { return m_iBufferSize / m_iAllocStep >= 1; }
+
+  wchar_t* GetAvailableBlock(int32_t& iIndexInBlock);
+  inline int32_t GetAllocStep() const { return m_iAllocStep; }
+  inline int32_t& GetDataLengthRef() { return m_iDataLength; }
+
+  inline void Reset(bool bReserveData = true) {
+    if (!bReserveData)
+      m_iStartPosition = 0;
+    m_iDataLength = 0;
+  }
+
+  void SetTextChar(int32_t iIndex, wchar_t ch);
+  int32_t DeleteTextChars(int32_t iCount, bool bDirection = true);
+  void GetTextData(CFX_WideString& wsTextData,
+                   int32_t iStart = 0,
+                   int32_t iLength = -1) const;
+
+ private:
+  inline void TextDataIndex2BufIndex(const int32_t iIndex,
+                                     int32_t& iBlockIndex,
+                                     int32_t& iInnerIndex) const;
+  void ClearBuffer();
+
+  std::vector<std::unique_ptr<wchar_t, FxFreeDeleter>> m_BlockArray;
+  int32_t m_iDataLength;
+  int32_t m_iBufferSize;
+  int32_t m_iAllocStep;
+  int32_t m_iStartPosition;
+};
+
+#endif  // CORE_FXCRT_CFX_BLOCKBUFFER_H_